Monday the 6th of Jan  3:45PM

Just looked at the ensembles of the GFS and EC.  Looking better for significant snow storm but pushed by to the 18th…

I still do not like that the MJO is not supporting this Pattern Change. Not sure why?

 

More Later.

 

SUNDAY PM 12-05-2020

 

Had a look at the new 12z runs of the GFS and ECM…  1st the operational models which can deviate quite a bit from the mean. However, if the change occurs close enough in time (72 Hours) You better take them seriously, especially if both are singing the same tune.  The GFS this morning is showing more retrogression the second half of week 2. Enough over water trajectory for a major storm. The ECMWF does show as much retrogression of the long wave, as its axis shifts from Utah to Eastern Nevada, not enough for an  AR or subtropical connection like the GFS does later week 2.  So what we have here is model agreement week 1 with a very cold Trof that deepens over the Great Basin with time this week. Some snow showers are possible anytime between Tuesday Night and Thursday AM. Colder weather yet next weekend as more modified Arctic Air pushes south, with light to possibly moderate snow fall Saturday into Sunday. Light (1 to 6 inches) Moderate (6 to 18 inches)

My sense today is upper end of the light, to possibly into low-moderate range. The main challenge is week 2. Looking at the MJO, it is strong and going into phases 4, which is wet for CA, then phases 5 and possibly 6.  The latter two are drier than normal for the state with phase 5 showing the best potential for eastern slopes up-slope snow with very cold temps.  Although there is not always coupling in the MJO teleconnection for the west coast, you have to use it and ERR this time to the drier ECMWF with its less retrogression. This is more like our past late fall and early winter WX pattern.  Note:  The Coldest Air arrives the end of this week into next week.

 

The Dweeber…….

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Latest GFS and ECMWF means are showing a pattern change….One of a deepening “cold” long wave Trof over the Great Basin, with its axis over Utah, according to the 7 day means. With this pattern comes much colder weather. There is definitely some modified arctic air that makes its way into our area over the next 6 to 10 days  However, with little over water trajectory, mainly light amounts of snowfall is expected through the middle of this week and most likely again next weekend, the 11th. For next weekend, there maybe slightly more over water influence, for a bit more snowfall next Saturday and Sunday 11-12th, but the fact remains that the long wave axis is still too far to the east next weekend for any big snows.  There appears to be a very strong short wave headed toward the west coast around the 15th or 16th the following week.. The Eastern Pacific high may retrograde enough to allow southwest flow to develop long enough for a good dump around that time. The Dweebs are still waiting for the Pacific to open up. It may take a bit longer though. With tonight’s modeling for the next 10 days, an AR is unlikely with this type of pattern. Only strong upper jet dynamics, squeezing what it can out of a fairly dry air mass..  Again, if one or more of these short waves is strong enough to carve back the long wave just a couple hundred miles, we could get quite a dump.   It would not be likely before the 15th….

On the positive side, if by chance, the Long Wave retrogrades westward, unlike the models are forecasting tonight, then that would change the Dweebs thinking for the Week 1-2 period.

 

 

This was your Saturday Night snap-shot

 

Dr Howard and the Dweebs………………………:-)